Starting treatment for Suspected PE: The Gospel According to NICE

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By Ben Balogun, ST5 EM Trainee.

Your Junior Clinical Fellow asks you to come and review a patient in your department complaining of breathless and chest pain with vital signs within acceptable limits and a normal ECG and CXR. She tells you that a Troponin was done at triage and is positive and she would like to treat the patient with ACS protocol refer to Cardiology for review. So you went to review the patient, upon entering the cubicle you note she is in a walking boot and a crutch by the bedside. The patient then tells you she had only just come out of a below knee cast following and ankle fracture which she feels hasn’t fully healed hence the boot. When asked, she also tells you she was not on any Venous Thromboembolism (VTE) prophylaxis during this period. She also has no significant past medical history and no other recent illness. So already my pretest probability for PE in this patient is high.

So as an ED Registrar in training and given your patient is currently stable and you know you’re not going to get a CT Pulmonary Angiogram for a number of hours yet, given your ED has been beset with multiple Trauma patients, you whip out your Ultrasound machine and performed a quick Transthoracic Echo. This showed a RV dilatation > 1:1 and you also noted a Right Ventricular systolic dysfunction.

What are the echocardiographic signs of RV dysfunction secondary to PE? (Rudoni et al.) (From Rebelem.com)

    • RV dilatation > 1:1 (normal ratio right: left ventricle is < 0.6:1)
    • Right ventricular systolic dysfunction
    • McConnell’s sign – mid RV wall hypokinesis with apical sparing
    • Moderate to severe tricuspid regurgitation
    • Paradoxical septal wall motion towards the left ventricle
    • Pulmonary artery dilatation
    • Atrial dilatation
    • Right heart thrombus or thrombus in transition
    • Lack of respiratory variation of the inferior vena cava

Also

  • Right atrial dilatation
  • D Shape deformation of the LV on parasternal short axis views

You are of course aware of other causes of RV strain such as COPD etc. and you also know that RV strain does not = PE!. However, you also recall a study by Grifoni et al, which suggested that a significant proportion of normotensive patients with acute PE presents with RV dysfunction. The study also goes on to say that these patient have a 10% rate of PE-related shock and 5% in-hospital mortality. Dresden et al in their study into bedside echocardiography performed by emergency physicians in the diagnosis of pulmonary embolism concluded that RV dilatation and RV Dysfunction found by ED physicians were highly specific for PE but had poor sensitivity. They went on to say bedside Echo is a useful tool that can be incorporated into the algorithm of patients with a moderate to high pre-test probability of pulmonary embolism.

Given all of the above, you asked your Junior Clinical Fellow to treat the patient for a suspected Pulmonary Embolism pending confirmation with CT Pulmonary Angiogram. It been a very busy trauma shift and you know Radiology will not be able to scan this patient for hours yet. However, your Clinical fellow asks you why not wait till we have a radiological confirmation before commencing treatment? She is concerned, rightly, that the patient may be having an ACS (Non ST elevation Myocardial Infarction), given the positive troponin. You recall that in the context of PE and RV dysfunction BNP and Troponin can be a diagnostic marker. Cotugno et al.

So at this point we turned to NICE (National Institute for Health and Care Excellence). What is the latest recommendation for managing a patient with suspected PE when radiological diagnosis may take a while.

JPulmonary embolism likely

Offer patients in whom PE is suspected and with a likely two-level PE Wells score either:

  • an immediate CTPA or
  • immediate interim parenteral anticoagulant therapy followed by a CTPA, if a CTPA cannot be carried out immediately.

Consider a proximal leg vein ultrasound scan if the CTPA is negative and DVT is suspected.
For patients who have an allergy to contrast media, or who have renal impairment, or whose risk from irradiation is high:

  • Assess the suitability of a V/Q SPECT scan or, if a V/Q SPECT scan is not available, a V/Q planar scan, as an alternative to CTPA.
  • If offering a V/Q SPECT or planar scan that will not be available immediately, offer immediate interim parenteral anticoagulant therapy.

Diagnose PE and treat patients with a positive CTPA or in whom PE is identified with a V/Q SPECT or planar scan (see the recommendations on treatment).
When to consider alternative diagnoses
Take into consideration alternative diagnoses in patients with a likely two-level PE Wells score and both:

  • a negative CTPA
  • no suspected DVT.

Advise these patients that it is not likely they have PE and discuss with them the signs and symptoms of PE, and when and where to seek further medical help.

Pulmonary embolism unlikely

Offer patients in whom PE is suspected and with an unlikely two-level PE Wells score a D-dimer test and if the result is positive offer either:

  • an immediate CTPA
  • immediate interim parenteral anticoagulant therapy followed by a CTPA, if a CTPA cannot be carried out immediately.

For patients who have an allergy to contrast media, or who have renal impairment, or whose risk from irradiation is high:

  • Assess the suitability of a V/Q SPECT scan or, if a V/Q SPECT scan is not available, a V/Q planar scan, as an alternative to CTPA.
  • If offering a V/Q SPECT or planar scan that will not be available immediately, offer immediate interim parenteral anticoagulant therapy.

Diagnose PE and treat patients with a positive CTPA or in whom PE is identified with a V/Q SPECT or planar scan (see the recommendations on treatment).
When to consider alternative diagnoses
Take into consideration alternative diagnoses in patients with an unlikely two-level PE Wells score and either:

  • a negative D-dimer test or
  • a positive D-dimer test and a negative CTPA.

Advise these patients that it is not likely they have PE and discuss with them the signs and symptoms of PE, and when and where to seek further medical help.

So as per NICE, the patient was treated for PE as soon as suspected and subsequently had CTPA (which was after the recommended time period) that confirmed the diagnosis.

 

References

1.Grifoni S, Olivotto I, Cecchini P, Pieralli F, Camaiti A, Santoro G, Conti A, Agnelli G, Berni G. Short-term clinical outcome of patients with acute pulmonary embolism, normal blood pressure, and echocardiographic right ventricular dysfunction. https://www.ncbi.nlm.nih.gov/pubmed/10859287

2.Dresden S, Mitchell P, Rahimi L, Leo M, Rubin-Smith J, Bibi S, White L, Langlois B, Sullivan A, Carmody K. Right ventricular dilatation on bedside echocardiography performed by emergency physicians aids in the diagnosis of pulmonary embolism. Ann Emergency Med, 2014 Jan; 6391): 16-24

3. Cotugno M, Orgaz-Molina J, Rosa-Salazar V, Guirado-Torrecillas L, García-Pérez B. Right ventricular dysfunction in acute pulmonary embolism: NT-proBNP vs. troponin T. Med Clin (Barc). 2017 Apr 21;148(8):339-344. doi: 10.1016/j.medcli.2016.11.023. Epub 2017 Jan 26.

4.Raymond R Rudoni MD, Raymond E Jackson MD, MSCorrespondence information about the author Raymond E Jackson, Gerald W Godfrey MD, Antonio X Bonfiglio MD, Mary E Hussey RD, MS, Andrew M Hauser MD. Use of Two-Dimensional Echocardiography for the Diagnosis of Pulmonary Embolus. The Journal of Emergency Medicine. http://www.ncbi.nlm.nih.gov/pubmed/9472752.

5.https://pathways.nice.org.uk/pathways/venous-thromboembolism

6. http://rebelem.com/diagnosis-right-ventricular-strain-transthoracic-echocardiography/#ITEM-1584-1

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